JPH0241644B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention connects a fluid pressure motor and a fluid pressure cylinder in parallel to a pump, and also includes a first sensor for detecting whether or not a piston of the fluid pressure cylinder is near a stroke end. a first flow control device for automatically reducing the amount of fluid supplied from the pump to the cylinder when the piston approaches the end of its stroke based on information from the first sensor; The present invention relates to an improvement in a fluid pressure drive device configured to relieve shock when a piston reaches the end of its stroke, and in particular, to an improvement in a flow rate control device.

Conventionally, in configuring the above-mentioned control device, for example, a third
As shown in the figure, a two-position flow control valve 23 that can be switched between a no-load state and a throttle state is provided in the supply path from the metering pump 25, and based on information from the sensor 22, the piston 21b reaches the stroke end. The controller 24 is configured to automatically switch the flow rate control valve 23 from the no-load state to the throttle state when the flow rate approaches .

However, since a sudden and large change in flow rate occurs as the flow rate control valve 23 is switched, for example, fluctuations in the buffer function may increase due to changes in the viscosity of the oil, or abnormal noises may occur as the viscosity of the oil increases. There were various drawbacks, such as an increase in oil temperature and a noticeable power loss due to increased flow resistance, and a lack of smooth operation of the cylinder 21.

An object of the present invention is to be able to eliminate the above-mentioned conventional drawbacks, and to have a configuration for that purpose.
The purpose is to avoid adverse effects on the drive of the fluid pressure motor connected to the same pump as the fluid pressure cylinder.

The characteristic configuration of the present invention is that the pump is configured as a variable displacement type, and a determination means is provided for determining whether or not the motor is in a driving state, and the first flow rate control device is configured to control the discharge of the pump. The device is configured to include an operating device that increases or decreases the amount, and a controller that controls the operation of the operating device based on information from the sensor, and the controller further includes:
The pump is further provided with a priority control means for setting the pump to a maximum discharge state based on information from the discrimination means, giving priority to information from the first sensor only when the motor is in a driving state.

The functions and effects of the characteristic configuration of the present invention are as follows. In other words, since the first flow rate control device can gradually reduce the amount of fluid supplied to the fluid pressure cylinder, it is possible to maintain a good buffering function that is almost constant even if the viscosity of the oil changes. Even if the amount of fluid supplied increases, the occurrence of abnormal noise can be effectively suppressed, and the cylinder can operate smoothly.Furthermore, since the discharge capacity of the pump itself is reduced, the pump's performance increases as the fluid supply volume decreases. As the load decreases and power efficiency improves,
Since there is no increase in fluid pressure, inconvenient situations such as increases in oil temperature can be eliminated, and in addition, when the fluid pressure motor is in the driving state, the pump is maintained at the maximum discharge state, so the fluid pressure motor This enables us to provide a hydraulic drive device that is superior to conventional ones in terms of overall operation, buffer function, and power efficiency, without causing inconvenient situations such as insufficient flow or insufficient pressure. It became.

Next, embodiments of the present invention will be described in detail based on illustrative drawings.

As shown in FIG. 1, a cylinder operating valve 3 and a motor operating valve 4 are used to drive and stop a hydraulic cylinder 1 and a hydraulic motor 2 installed in construction machinery, agricultural machinery, and various other devices, respectively. It is connected in parallel to the variable displacement pump 5 via the pump.

A ring-shaped proximity switch 6 is attached to the tube 1a of the cylinder 1 so as to surround the outer circumferential surface of the tube 1a, and as the piston 1b approaches the proximity switch 6, the magnetic field of the proximity switch 6 changes. The arrangement is such that an electric signal is sent from the proximity switch 6 to the controller 7 to notify that the piston 1b has approached the end of its stroke based on changes in the magnetic field.

A spring recovery type single-acting cylinder 8 for changing the discharge amount of the pump 5 is provided, and between the cylinder 8 and an auxiliary pump 9 that drives it,
An electromagnetic flow switching valve 10 that is automatically operated by the controller 7 is provided, and when the proximity switch 6 notifies that the piston 1b approaches the stroke end, the controller 7 automatically switches the valve to the single-acting cylinder 8
The flow path switching valve 10 is configured to be automatically operated to gradually reduce the discharge amount of the pump 5 by driving the auxiliary pump 9.

In this way, the proximity switch 6, the controller 7, the flow path switching valve 10, the auxiliary pump 9, and the spring recovery type single acting device 8 constitute a first flow rate control device.

A micro-switch type cylinder system position detection sensor 1 detects whether the cylinder operation valve 3 and the motor operation valve 4 are in a driving state.
1 and a motor system position detection sensor 12 are provided, and based on the information from these sensors 11 and 12, it is determined that each of the operating valves 3 and 4 has been switched from a driving state to a stopped state. A cylinder system discrimination circuit 13 and a motor system discrimination circuit 14 are provided to notify the controller 7 of the cylinder operation valve 3 after driving the single acting cylinder 8.
When the pump 5 is switched to a stopped state, the spring 8 causes the single-acting cylinder 8 to increase the discharge amount of the pump 5.
When the flow path switching valve 10 is automatically operated by the controller 7 and the motor operation valve 4 is in the driving state to connect to the tank 15 to be restored in step a, the above-mentioned input to the controller 7 is performed. The flow path switching valve 10 is automatically operated by the controller 7 in order to maintain the single-acting cylinder 8 connected to the tank 15 so that the pump 5 is in the maximum discharge state with priority over all other signals. It is configured so that

In this way, the controller 7 controls the motor 2.
Based on information from a motor system discrimination circuit 14 serving as a determining means for determining whether or not the motor 2 is in a driving state, the pump 5 is provided with a priority control means for setting the discharge state to the maximum discharge state.

Next, another example will be described.

In order to detect whether or not the piston 1b is close to the stroke end, for example, as shown in FIG. Various configuration changes are possible, such as having the controller 7 perform position detection based on whether the information value from the detector 16 is within the set range, and the configuration for such detection can be changed to the proximity switch 6, 16. Collectively called.

In order to reduce the discharge amount of the pump 5, various configuration changes can be made, such as interlocking a drive device such as an electric motor or an air cylinder with the pump's discharge amount adjustment operation unit and having it automatically operated by the controller 7. The configuration for adjusting the discharge amount is collectively referred to as the operating device 8.

In addition, in order to detect whether or not the fluid pressure motor 2 is in a driving state, various configuration changes are made, such as providing a micro switch on the motor operating lever etc. in place of the micro switch type position detection sensor 12 for the motor operating valve 4. are possible, and they are collectively referred to as the second sensor 12.

The motor system discriminating circuit 14 is used as discriminating means for discriminating the drive state of the fluid pressure motor from the detection results of these second sensors 12.

The specific configuration for linking the first sensors 6, 16 and the second sensor 12 with the operating device 8 can be easily modified in various ways from the viewpoint of control technology, and the target cylinder 1 is an air cylinder. etc., and any fluid pressure cylinder may be used.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the fluid pressure drive device according to the present invention, FIG. 1 is a hydraulic pressure and control circuit diagram, FIG. 2 is a hydraulic pressure and control circuit diagram showing another embodiment, and FIG. 3 is a conventional example. FIG. 3 is a hydraulic and control circuit diagram. 1... Cylinder, 1b... Piston, 2... Motor, 5... Pump, 6, 16... First sensor, 7... Controller, 8... Operating device, 12... Second sensor, 14... ...discrimination means.

Claims (1)

[Claims] 1. The fluid pressure motor 2 and the fluid pressure cylinder 1 are connected in parallel to the pump 5, and a first sensor 6, 16 detects whether the piston 1b of the fluid pressure cylinder 1 is near the stroke end or not.
and a first flow rate control for automatically reducing the amount of fluid supplied from the pump 5 to the cylinder 1 when the piston 1b approaches the stroke end based on information from the first sensors 6 and 16. The pump 5 is of a variable displacement type, and a determining means 14 is provided for determining whether or not the motor 2 is in a driving state, and the first flow rate is The control device includes an operating device 8 that increases or decreases the discharge amount of the pump 5, and a controller 7 that controls the operation of the operating device 8 based on information from the sensors 6 and 16. , furthermore, the controller 7
comprises priority control means for setting the pump 5 in a maximum discharge state based on the information from the discrimination means 14, giving priority to the information from the first sensors 6 and 16 only when the motor 2 is in the driving state. A fluid pressure drive device characterized by: